Refractory article and method of making the same



s. c. LIINBARGER.

REFRACTORY ART ICLE AND METHOD OF MAKING THE SAME.

APPLICATION FILED OCT. 31. 1918.

1,345, 377. Patented uly 6, 1920.

SILICON CARBIDE 207 509 To 85 S/L/COIL pm CARBIDEIAND FIRE cuy WITNESSES INVENTOR UNITED STATES PATENT OFFICE.

SILAS C. LIN'BABGER, OF NIAGARA FALLS. NEW YORK, ASSIG NOB TO THE CABlBO- BUN'DUM COMPANY, OF NIAGARA FALLS, NEW YORK, A CORPORATION OF NEW YORK.

REFRACTORY ARTICLE AND METHOD OF MAKITI'G THE SAME;

Patented Jul aieao,

Application filed October 31, 1918. Serial No. 280,448.

To all whom it may concern:

Be it known that 1, Sims C. residing at Niagara Falls, in the county of Niagara and State of New York, have invented a new and useful Improvement in V Refractory Articles and Methods of Making the Same, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, forming part of this specification, in whichl Figure 1 is a sectional view illustrating one step in the manufacture of my improved article Fig. 2 is a sectional view of a portion of the finished article. 4

My invention relates to refractory articles containing silicon carbid, andmore especially to a composite article having one side or face consisting largely or wholly of silicon carbid with a body or backing in which fireclay or other refractory material predominates.

Refractory articles containing a considerable percentage of silicon carbid' have proved of great value in man locations where they are exposed to high temperature conditions. They withstand intense 'heat and are neutral to the action of many chemical substances. Theyvare, however, relatively more expensive than similar articles composed wholly of firec'lay materials, and are much better conductors of heat.

While the high thermal conductivity of silihave been satisfactory from a refractory point of view, but owing to the unequal expension of the carborundum facing and the fireclay backing under heat, the coating is very apt to spall off and fall away. It

LINBARGER',

' irregular.

has also been proposed to make firebrickin which a: facing of silicon carbid about one inch inthickness was secured to the brick proper by a dove-tailed rib-and-grooveengagement. This is also satisfactory from a refractory point of view, but in use, especially in boiler furnaces, the silicon carbid piecesare apt to be fractured by the firemen and fall off.

My invention provides a firebrick or other refractory article comprisin successive layers, one layer forming one ace of the brick or other article containing suflicient silicon carbid to combine the best refractory and chemically resistent properties desired .for

the particular purpose inview. The successive layers contain progressively less silicon carbid and more fireclay, silica or other refractory material. I A

My inventioncan be used either with the dry-pressed process 'or the wet process of making firebrick. In either case, it is desirable to roughen up the surface of a preceding layer before applying the next layer, so as to cause the layers to be knitted together as closel as possible. For example, in making a ry pressed brick, the layer containing the hlgher or highest percentage of silicon carbid is first added in. the bottom of the mold, struck off to make it substantially even in thickness, and then combed up in a manner to leave its surface rough and The nextlayer is then added and treated in the same manner- After the full amount of material has been placed in'the mold, it is pressed, after which the layers will be found to have been closely knitted to ether.

The di erence in the coeflicient of expansion of the successive layers is relatively slight, and there is, therefore, little or no tendency for one layer to flake off from the next layer. Furthermore, owing to the comparatively little'diiference in the amount and character of the bonding material in the adjacent layers, a good ceramic union between the layers isformed. A further advantage of the invention is that a wall built up of brick of this character does not have a high thermal conductivity, since the bulk of the wall is composed of fireclay of low thermal conductivity.

'der boilers, furnaces and in man ahi hl-yrefractoryurnace 1s Bricks of this character are of great utility when used in the linings of furnaces unkiln furnaces,

other locations where desirable. y invention islalso. applicable to many other refractory forms besides bricks; It

may, for example, be used-in themanufac-j ture of bats or shelves employed inthe placing of pottery in potters kilns. Forsuch purpose, have found it advantageous to make the lower portion of the bat of a mixture containing-from 50 to 85% .silicon car- I silicon carbid has a certain reducing and portions of manufacture of bid, and the balance of fireclay. I then use i an intermediate portion or layer consisting preferably of about 20% of silicon carbid and a final layer which consists of pure fire I clay without any silicon carbid. Such bats or shelves are advantageous in theburning of certain classes of ceramic ware where discolorin'g action onthe ware, since the the refractories in contact with the ware are fireclay.

My invention may also be used in the glass pots and the like, outside portion being composed of a high sil'iconcarbid mix, and the inner portions, which are subjected to the action of'glass containing either a small proportion of siliconcarbid or none at all.

Many other applications of my invention will occur to those skilled in the art.

In Fig. 1 of my invention, 1 have illustrated the manner in which the successive layers of formingmaterial 2, 8 and 4 may be placed in a suitable mold 5, the surface of each layer being roughened before applying the next layer. Fig. 2 illustrates a section of a finished article constructed in accordance with my invention. It will be noted that in the latter, the layers while firmly k-nit together are nevertheless preserved intact, so that each layer retains its initial characteristics with respect to theamount of silicon carbid it contains. v

I do not limit myself to the employment of three layers, since a greater number may be employed, if desired, with a more gradual brass -melting tion consisting substantially the .ing lireclay as lts predominating element. the opposite outer layer having silicon carbid as its predominant element and forming the facing portion of the article, the silicon carbid bGIIIg PIOPOP-ClOIIQLl' in said layers in such decreasing amountsfrom the facing layer inward as will ive a graduated and increasing coefiicient 0 expansion from said facing portion inward.

3. he method of making refractory articles composed mainly of silicon carbid and refractory binding material, which consists in forming superimposed layers, one of which forms a facing layer, and proportioning the silicon carbid in such decreasing amounts from the facingportion inward as will give a graduated and increasing 'coefficient of expansion from said facing portion inward, and compressing said layers together into a unitary mass. 7

i. The method of forming refractory articles composed mainly of silicon carbid and a refractory bonding material, which consists in forming superimposed layers of the forming material in a suitable mold, the diflerent layers having different predetermined proportions of silicon carbid and bonding material, shaping the adjoining surfaces of the different layers in a manner to cause them to unite together, and pressing the several layers into a unitary mass or body. In testimony whereof I have hereunto set my hand.

SILAS C. LINBARGER. 

